Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F14/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
  • C08F14/18—Monomers containing fluorine
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2438/00—Living radical polymerisation
  • C08F2438/01—Atom Transfer Radical Polymerization [ATRP] or reverse ATRP

Definitions

• the present invention relates to an easily cross linkable fluorine-containing polymer. More particularly, it relates to an easily cross linkable fluorine-containing polymer containing a certain specific amount of linked bromine in the molecule and a cross linkable composition comprising said fluorine-containing polymer.
• Fluorine-containing polymers in an elastic or non-elastic state are often subjected to cross linking for the purpose of enhancing their characteristic properties such as mechanical strength, liquid resistance and creep resistance. Thus, it is greatly advantageous that those polymers can be easily cross linked.
• an easily cross linkable fluorine-containing polymer comprising: (1) a polymeric chain comprising one or more polymer segments, at least one polymer segment of which consists of units of at least one fluorine-containing ethylenically unsaturated compound having 2 to 8 carbon atoms, or units of said fluorine-containing ethylenically unsaturated compound and at least one other monomer selected from the group consisting a fluorine-free ethylenically unsaturated compound having 2 to 4 carbon atoms and a fluorine-containing diene having 4 to 8 carbon atoms, (2) at least one bromine atom liberated from a brominated compound of the formula: RBr x (wherein R is a saturated hydrocarbon residue and x is a number corresponding to the bonding valency of the residue R) in an amount of 0.001 to 10% by weight based on the polymer weight and (3) a fragment of the brominated compound excluding the said liberated bromine
• the fluorine-containing polymer containing linked bromine of the invention is more stable than the fluorine-containing polymer containing linked iodine since bromine atom has less tendency to be cleaved from the molecule than iodine when the polymer is lightened.
• the brominated compound is comparatively more easily handled and obtainable than the iodinated compound. Further, when the brominated compound is used, the rate of polymerization is less deteriorated, and control of the molecular weight is easier.
• linked bromine herein used is intended to mean a bromine atom linked to a carbon atom in the chain of the fluorine-containing polymer.
• bromine is linked to the terminal carbon atom(s).
• Bromine atoms are rarely linked to an intermediate carbon atom other than the terminal carbon atoms.
• the linkage between the bromine atom and the terminal carbon atom can contribute effectively to the cross linking on the curing of the fluorine-containing polymer.
• the amount of linked bromine depends on the molecular weight of the polymer and is usually from about 0.001 to 10% by weight, preferably from about 0.01 to 5% by weight.
• the amount of linked bromine is smaller than 0.001% by weight, curing of the polymer is insufficient.
• it exceeds 10% by weight the heat resistance of the polymer is deteriorated.
• the amount of linked bromine per a molecule of the polymer is not particularly limited, provided that it is essentially one or more and the total amount of linked bromine does not exceed 10% by weight.
• the carbon-bromine (C--Br) linkage of the brominated compound is a relatively weak one and is easily cleaved radically in the presence of a radical producing source.
• the high reactivity of the thus produced radical causes the addition growth of the monomer, and then the bromine atom is taken out from the brominated compound to stop the reaction, whereby the fluorine-containing polymer in which bromine is linked to the carbon atom at the terminal of the molecule can be obtained.
• the thus formed linkage of the terminal of the fluorine-containing polymer with bromine is again cleaved radically with ease in the presence of a radical producing source to produce a radical having a similar reactivity.
• the addition growth of the monomer is caused at each polymerization step as mentioned above to afford a fluorine-containing segmented copolymer in which two or more kinds of segments corresponding to the kind of each monomer are chemically linked and linked bromine is present.
• the fluorine-containing polymer of the invention may comprise a homopolymer or random copolymer consisting of a polymeric chain in which substantially two or more kinds of segments are chemically linked. Especially, the latter possesses various interesting properties which can not be obtained by conventional blending processes.
• the polymeric chain may consist of (1) a homopolymer segment or random copolymer segment comprising units of at least one fluorine-containing ethylenically unsaturated compound; (2) a random copolymer segment comprising units of at least one fluorine-containing ethylenically unsaturated compound and at least one fluorine-free ethylenically unsaturated compound copolymerizable therewith; (3) a segmented copolymer comprising at least two kinds of the polymer segments (1) which are chemically linked; (4) a segmented copolymer comprising at least two kinds of the copolymer segments (2) which are chemically linked; (5) a segmented copolymer comprising at least one kind of the polymer segment (1) and at least one kind of the copolymer segment (2); and (6) a segmented copolymer comprising at least one kind of the polymer segments (1) or (2) and a polymer segment comprising the fluorine-
• each segment in the polymeric chain consists of two or more kinds of monomers
• the same kinds of monomers may be used in varying proportion.
• the constituting segments are not necessarily required to be different from each other in the whole portions of the polymeric chain.
• the sufficient condition is that at least two kinds of segments are present in the polymeric chain and at least one of them is a fluorine-containing segment.
• the brominated compound contains one or two linked bromine atoms and is stable to such an extent as undesirable side reactions do not proceed under the polymerization conditions.
• R is a saturated hydrocarbon residue (which may include a functional group such as --O--, --S--, RN ⁇ , --COOH, --SO 3 H, and --PO 3 H) usually having 1 to 8 carbon atoms.
• Preferred examples of the brominated compound are CF 2 ClBr; CF 2 Br 2 , BrCF 2 CF 2 Br, CF 3 CFBrCF 2 Br, CH 2 ClBr, CF 3 Br, CH 3 Br, CFClBr 2 , CCl 3 Br, CBr 4 , CF 2 ClCFClBr, CF 2 ClCCl 2 Br, CF 2 BrCFClBr, CFBrClCFClBr, CF 2 BrCF 2 CF 2 Br, CF 2 BrCFBrCF 2 Br, CF 2 HCF 2 Br, CF 2 HCFClBr, CH 2 BrCF 2 H, CF 2 BrCFH 2 , CH 2 BrCH 2 F, CF 2 BrCFHCl, CH 3 CF 2 Br, CF 2 HCFHBr, CH 3 CHFBr, CF 2 HCFBrCF 3 , CF 2 BrCFHCF 3 , (CF 3 ) 2 CBrCH 3 , CF 2 HCFBrOCF 3
• fluorine-containing ethylenically unsaturated compound examples include tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, chlorotrifluoroethylene, hexafluoropropylene, pentafluoropropylene, perfluorocyclobutylene, perfluoro(methylcyclopropylene), perfluoroallene, ⁇ , ⁇ , ⁇ -trifluorostyrene, perfluorostyrene, perfluoroalkyl vinyl ethers (eg.
• fluorine-free ethylenically unsaturated compound which is copolymerizable with the fluorine-containing ethylenically unsaturated compound are ethylene, propylene, butylene, vinyl carboxylate (eg. vinyl acetate), vinyl ethers (eg. methyl vinyl ether, ethyl vinyl ether), etc.
• the fluorine-containing polymer favorable for the cross linking property is the one containing substantially a an elastomeric random copolymer of vinylidene fluoride with at least one other fluoroolefin copolymerizable therewith.
• the most favorable one is said elastomeric random copolymer containing 30 to 65% by weight, preferably less than 50% by weight of vinylidene fluoride units and having a number average molecular weight of about 8,000 to 400,000 (determined by the osmotic pressure method).
• fluoroolefines examples include tetrafluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, trifluoroethylene, vinyl fluoride, hexafluoropropylene, pentafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), etc.
• the fluorine-containing dienes are those having 4 to 8 carbon atoms, examples of which are those consisting of two terminal residues (a) CF 2 ⁇ CF--, CF 2 ⁇ CH-- or CF 2 ⁇ CFO-- and a divalent intermediate residue (b) --(CF 2 ) n --, --(CF 2 O) x --(CF 2 CF 2 O) y --CF 2 -- or ##STR1## wherein n is an integer of 0 to 8, and x, y and z are each an integer of 0 to 8 and satisfy the equation: 0 ⁇ x+y+z ⁇ 8, with the proviso that when n is 0, the residue (a) is other than CF 2 ⁇ CFO--.
• dienes in which the residue (a) is CF 2 ⁇ CF-- or CF 2 ⁇ CFO-- and the residue (b) is --(CF 2 ) n -- or --(CF 2 O) x --(CF 2 CF 2 O) y --CF 2 -- are preferred.
• the molar ratio of said diene and the fluorine-containing ethylenically unsaturated compound in the polymer is 5 ⁇ 10 -2 or less.
• said diene is used more than this limit, the polymer is too hard, processability such as roll milling is deteriorated and elongation of the cross linked polymer is less.
• the radical producing source to be used in the production of the fluorine-containing polymer light or heat may be preferably employed.
• infrared to ultraviolet rays particularly not containing actinic ultraviolet rays, may be used.
• Actinic ultraviolet rays may produce radicals also from linkages other than the I--Br linkage and is thus not necessarily ideal.
• a temperature of at least 100° C., preferably 200° C. or higher is required.
• Ionizing radiation may be also utilized, but it produces radical indiscriminately in essence and is thus undesirable.
• radical initiators such as inorganic or organic peroxides, azo compounds, organometallic compounds and metals may be also employed depending on the mode of the polymerization.
• the preferred radical initiators are persulfates, hydrogen peroxide, (R'CO) 2 O 2 , R'OOR', (R') 3 COOC(O)OC(R') 3 , N 2 F 2 , R'--N ⁇ N--R', HgR' 2 (R' being, same or different, a polyfluoroalkyl group), Li, K, Na, Mg, Hg, Al, etc.
• the polymerization temperature may be optionally selected from such range as the radical reaction takes place but thermal decomposition of the produced polymer chain does not occur. Usually, a temperature of -20° C. to 150° C. is adopted. In case of using heat as the radical producing source, a higher temperature, sometimes of about 250° C. is necessary.
• the polymerization pressure is not critical and usually equal to or lower than the autogeneous pressure of the monomers participating in the polymerization.
• the medium for solution polymerization one in which chain transfer is hardly caused is preferred.
• the following solvents may be favorably employed: ##STR2## CF 2 ClCF 2 Cl, CF 2 ClCFCl 2 , H(CF 2 ) n H, ##STR3## CF 3 O(C 2 F 4 O) n CF 2 CF 3 , N(C 4 F 9 ) 3 , etc.
• emulsifier In case of emulsion polymerization, the use of emulsifier is usually desirable. When the produced polymer has a surface active effect, for instance, in case of containing a hydrophilic group such as --COOM, --OH or --SO 3 M (M being hydrogen, metal or any other cation), the use of an emulsifier in not necessarily required.
• a fluorine-containing one such as a salt of fluorine-containing carboxylic acid or fluorine-containing sulfonic acid is favorably employed.
• the amount of the emulsifier to be used is usually 5% by weight or less to the amount of water.
• a chain transfer agent may be also employed, but generally a desirable result is not obtained.
• any of the fluorine-containing polymers in liquid or solid state may be employed, provided that it contains the C--Br bond.
• Some of the fluorine-containing polymers show an intrinsic viscosity [ ⁇ ] (dl/g) of about 0.01 or larger, preferably 0.15 to 2.0, when determined at 35° C. in a solvent being able to dissolve the polymer (for instance, the solvent described in Examples below).
• the brominated polymer, particularly the brominated elastomeric copolymer of the invention is cross linkable characteristically as mentioned above in the presence of a cross linking source.
• a cross linking source high energy electromagnetic waves such as radioactive rays (eg. gamma rays, electron rays, alpha rays, beta rays, X-rays) and ultraviolet rays may be employed, but the use of cross linking agents such as organic peroxides, polyamines, polyhydroxy compounds and polythiols are more favorable.
• the organic peroxides or the polyamines are used as the cross linking agent, the copolymer of the invention shows characteristic cross linking properties, and the cross linked copolymer has improved physical properties.
• the copolymer containing the linked bromine in the molecule, particularly the elastomeric copolymer of the invention can be cross linked with the peroxides more easily than a fluorine-containing elastomeric polymer not containing bromine.
• the polyamine is used as the cross linking agent, the rate of the cross linking is improved, and when the peroxide is used, the compression set of the cross linked polymer is improved.
• the amount of such cross linking agent to be used is usually from 0.05 to 10 parts by weight, preferably from 1.0 to 5 parts by weight to 100 parts by weight of the polymer.
• the organic peroxide the one readily producing a peroxy radical under heating or in the oxidation-reduction system is usually desired.
• peroxides are 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroxyperoxide, di-t-butylperoxide, t-butylcumylperoxide, dicumylperoxide, ⁇ , ⁇ '-bis(t-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexene-3, benzoylperoxide, t-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylper
• a remarkable effect can be obtained by the combined use of a cross linking aid or a co-cross linking agent.
• a cross linking aid or co-cross linking agent any one having a reactivity to peroxy and polymer radicals may be effectively employed in principle.
• Preferable examples are trially cyanurate, triallyl isocyanurate, triacrylformal, triallyl trimellitate, N,N'-m-phenylenebismaleimide, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalamide, triallyl phosphate, etc.
• the amount to be used is 0.1 to 10 parts, preferable 0.5 to 5 parts to 100 parts of the polymer.
• silicone oil, silicone rubber, ethylene-vinyl acetate copolymer, 1,2-polybutadiene, fluorosilicone oil, fluorosilicone rubber, fluorophosphazen rubber, hexafluoropropylene-ethylene copolymer, tetrafluoroethylene-propylene copolymer and other polymers having radical reactivity or amine activity may be also employed.
• the fluorine-containing polymer of the invention which can have an olefin structure by bromine eliminating reaction by utilizing the reactivity of the terminal bromine is also used as the blendable co-cross linking substance.
• the amount of such substance to be used is not particularly limited, but it is not desirable to use it in such a large amount as deteriorating the essential quality of the fluorine-containing polymer.
• the polyamine may be a primary or secondary amine having two or more basic nitrogen atoms in the molecule. In many cases, it is used in a salt form so as to make the reactivity milder. In usual, the use of alkylenediamines, especially, ethylenediamine carbamate, hexamethylenediamine carbamate, 4,4'-diaminocyclohexylmethane carbamate, etc. is preferable. Schiff's bases such as N,N'-dicinnamylidene-1,6-hexamethylenediamine are also employed frequently. Further, poorly basic aromatic polyamines may be employed advantageously in combination with other basic compounds.
• Examples of the other basic compounds are diphenylguanidine, di-O-triguanidine, diphenylthiourea, 2-mercaptoimidazoline, etc. Accelerators for synthetic rubbers containing --NH 2 and/or --NH-- in the molecule, divalent metal hydroxide and the like are also usable.
• the amount of the polyamine compound to be used is about 0.5 to 5 parts to 100 parts of the polymer.
• polyhydroxy compound there may be employed polyhydroxy compounds containing an enol type hydroxy group ##STR4## dihydroxy compounds represented by the formula: R"(CH 2 OH) 2 (wherein R" is a polyfluoroalkylene or perchlorofluoroalkylene group having 1 to 20 carbon atoms) or their alkali metal salts, or their mixture.
• Such compounds are hydroquinone, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)perfluoropropane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)methane, 4,4'-dihydroxydiphenyl ether, HOCH 2 (CF 2 ) 3 CH 2 OH, HOCH 2 CF 2 CFH(CF 2 ) 3 CFHCF 2 CH 2 OH, HO(CH 2 ) 3 (CF 2 ) 3 (CH 2 ) 3 OH, HOCH 2 CF 2 CH 2 (CF 2 ) 3 CH 2 CF 2 CH 2 OH or their alkali metal salts.
• polythiols aliphatic or aromatic dithiols are usually employed. Specific examples thereof are dimercaptodimethyl ether, dimercaptomethyl sulfide, 1,6-hexanedithiol, ethylenebismercapto acetate, 1,5-naphthalene dithiol, 4,4'-dimethylmercaptodiphenyl, triazine-substituted thiol or their alkali metal salts.
• the cross linking of the polymer of the invention is effected in the presence of a divalent metal oxide or hydroxide as an acid acceptor in addition to the above mentioned cross linking source.
• the divalent metal oxide or hydroxide may be, for example, an oxide or hydroxide of Ca, Mg, Pb, Zn, etc. Their complex salts may be also utilizable. These compounds not only serve as the acid acceptor but also contribute to improvement of the cross linking reactivity, the mechanical properties and the heat resistance.
• cross linking accelerators such as tertiary amines, trisubstituted amidines, pentasubstituted guanidines or their organic or inorganic acid salts, quarternary ammonium salts or quarternary phosphonium salts may be also employed.
• cross linking accelerators detailed description is given in Japanese Patent Publication (unexamined) Nos. 56854/1976, 1387/1972 and 191/1972.
• weak acid salts of monovalent metal such as Na, K, Ag and Cu may be employed.
• composition of the invention may also contain pigments, fillers, reinforcing agents, etc.
• the fillers or the reinforcing agents are carbon black, TiO 2 , SiO 2 , clay and talk as inorganic materials and fluorine-containing polymers such as polyteterafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, tetrafluoroethylene-ethylene copolymer and tetrafluoroethylene-vinylidene fluoride copolymer as organic materials.
• the mixing of the above compounds may be effected by an appropriate procedure depending on their visco-elasticity and state.
• a conventional open roll or powder mixer is usable.
• a conventional mixer may be employed. It is also possible to dissolve or disperse the solid compounds to obtain a dispersed mixture.
• the fluorine-containing polymer of the invention may be used, for example, as a plastic material, a sealant, an adhesive or a paint in the field where resistances against heat, oil, chemicals, solvents, etc. are highly desired.
• Example 2 In the same manner as in Example 1 but using CF 2 BrCF 2 Br (5.50 ⁇ 10 -3 mol) in place of CF 2 ClBr, using 0.50 g of ammonium persulfate and effecting the reaction for 185 minutes, polymerization was carried out to obtain an aqueous emulsion containing 24.6% by weight of solid.
• the obtained elastomeric polymer had an intrinsic viscosity [ ⁇ ] of 0.77 dl/g (35° C. in tetrahydrofuran) and contained 1,100 ppm of bromine.
• Example 3 In the same manner as in Example 3 but using 7.75 g of CF 3 CFBrCF 2 Br and effecting the reaction for 19 hours, polymerization was carried out to obtain an aqueous emulsion containing 12.5% by weight of solid.
• the obtained elastomeric copolymer had an intrinsic viscosity [ ⁇ ] of 0.66 dl/g (35° C. in tetrahydrofuran) and contained 1,200 ppm of bromine.
• a vulcanization test of the composition was effected by the aid of a JSR Curastometer II type. 100% Tention (M 100 ), tensile strength (T B ), elongation (E B ) were measured according to JIS K 6301. The results are shown in Table 2.
• TFE tetrafluoroethylene
• VdF/HFP molar ratio, 16.5:46.5:37.0
• ammonium persulfate was consumed and the reaction rate was decreased. After 110 minutes, in order to maintain the reaction rate, ammonium persulfate was continuously charged at a rate of 12 mg/min. by means of a pump under pressure. After 130 minutes, the temperature was lowered rapidly and unreacted monomers were discharged to terminate the reaction. An aqueous emulsion was obtained.
• Vulcanization test of the composition was effected by the aid of a JSR Curastometer II type. 100% Tention (M 100 ), tensile strength (T B ), elongation (E B ), hardness and compression set (CS) were measured according to JIS K 6301. The results are shown in Table 4.

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• 1982
  • 1982-07-27 JP JP57130781A patent/JPS5920310A/ja active Granted
• 1983
  • 1983-07-26 DE DE8383107316T patent/DE3375398D1/de not_active Expired
  • 1983-07-26 EP EP83107316A patent/EP0101930B1/en not_active Expired
  • 1983-07-26 US US06/517,334 patent/US4501869A/en not_active Expired - Lifetime

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